Plotting series histogram in Pandas

Question

I am plotting a series histogram in Pandas as follows:

df['Primary Type'].value_counts().plot(kind='bar')

Nevertheless, this series have 25 unique values and the plot draws many bars. Is it possible to group the bars with lower frequency in only one?

Thank you in advance.

Answer 1

You can use pd.cut to make histogram bins -

# Example Dataframe
df = pd.DataFrame({'a' : [25, 22, 22, 21, 45, 20, 1, 1, 1, 1, 2, 3, 4, 4, 4]})

cuts = pd.cut(df['a'], [0, 10, 50])
cuts.value_counts().plot(kind='bar')

Answer 2

You can do it by filtering by boolean indexing:

np.random.seed(100)
df = pd.DataFrame(np.random.randint(20, size=(20,1)), columns=['Primary Type'])
print (df)
    Primary Type
0              8
1              3
2              7
3             15
4             16
5             10
6              2
7              2
8              2
9             14
10             2
11            17
12            16
13            15
14             4
15            11
16            16
17             9
18             2
19            12

---

s = df['Primary Type'].value_counts()
print (s)
2     5
16    3
15    2
17    1
14    1
12    1
11    1
10    1
9     1
8     1
7     1
4     1
3     1
Name: Primary Type, dtype: int64

#all values under trash sum to one category
tresh = 2
a = s[s <= tresh].sum()
s = s[s > tresh]
#then add to filtered df
s.loc['another'] = a
print (s)
2           5
16          3
another    12
Name: Primary Type, dtype: int64

#last plot
s.plot(kind='bar')